As a rule, the reciprocating hermetic compressors present, at the suction side thereof, an acoustic dampening system (acoustic filters or suction mufflers), which is provided inside the shell and which conducts the gas coming from the suction line to the suction valve.
This component has several important functions to the adequate operation of the compressor, such as gas directing, acoustic dampening and, in some cases, thermal insulation of the gas being drawn into the cylinder.
The adequate thermal insulation of the gas being drawn is important to improve the volumetric and energetic efficiencies of the compressor.
During the time elapsed between the admission to the compressor and the admission to the cylinder thereof, the gas temperature is increased, due to heat transferred thereto from the several hot sources existing inside the compressor. The temperature increase of the gas causes an increase in its specific volume and consequently reduces the mass flow of the refrigerant pumped by the compressor. Since the refrigeration capacity of the compressor is directly proportional to the mass flow, reducing said flow results in efficiency loss.
In order to achieve adequate thermal insulation, the current mufflers are usually produced in a material of low thermal conductivity, such as for example, resins, plastic, having good thermal insulation property.
There are known in the art the suction mufflers constructed of injected plastic material and comprising a hollow body, which is provided with gas inlet and gas outlet nozzles and, internally, with a plurality of chambers disposed in a consecutive arrangement and in a linear sequence, and which are maintained in fluid communication in relation to each other and to the gas inlet of the compressor through a duct having an end connected and opened to the gas inlet nozzle of the hollow body; median windows, which are longitudinally spaced from each other and opened to respective chambers; and an opposite end opened to a last chamber of the linear sequence and which is maintained opened to the gas outlet of the hollow body.